Method and apparatus for efficient GPS assistance in a communication system

• US 6,058,338 A
• Filed: 02/12/1999
• Issued: 05/02/2000
• Est. Priority Date: 02/12/1999
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Soliman, Samir S., Agashe, Parag A., Vayanos, Alkinoos Hector
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Hernandez, Olga
• Application Number:
  US09/250,771
• Time in Patent Office: 445 Days
• Field of Search: 701/13, 701/213, 244/158 R, 356/139.01, 342/355
• US Class Current: 701/13
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/07 providing data for correcting measured positioning data, e.g. DGPS [differential GPS] or ionosphere corrections
• CPC Class Codes: G01S 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
• CPC Class Codes: G01S 19/27 creating, predicting or correcting ephemeris or almanac data within the receiver

Abstract

A method and apparatus for efficiently transmitting location assistance information to a mobile communication device over a control channel with a minimal impact on the capacity of the control channel. A position location server provides a difference between satellite locations which have been computed using Almanac data and then Ephemeris data. Sending only the difference between the locations and clock corrections computed using the two different data types, the total amount of information to be transmitted to a mobile communication device is significantly reduced. Furthermore, by providing rate of change information, the method and apparatus allows the location assistance information to remain valid for a relatively long time after it is has been received by the mobile communication device.

Claims

1. A method for calculating the position of a satellite, including the steps of:

a) transmitting Almanac data to a mobile communication device;

b) computing the location of the satellite at a first point in time using the transmitted Almanac data;

c) computing the clock correction for the satellite at the first point in time using the transmitted Almanac data;

d) computing the location of the satellite at the using Ephemeris data at the first point in time;

e) computing the satellite clock correction for the satellite at the first point in time using the Ephemeris data;

f) computing difference between the location and satellite clock correction computed using the transmitted Almanac data and the location and clock correction using the Ephemeris data; and

g) transmitting to the mobile communication device the computed differences.

2. A server for calculating information that assists in locating the position of satellites, including:

a) an output port capable of outputting an Almanac and satellite location information, including information regarding the difference between clock corrections and locations computed based upon Almanac and Ephemeris data; and

b) a processor, coupled to an output port, capable of;

i) computing the location of a satellite based upon the Almanac;

ii) computing the satellite clock correction based upon the Almanac;

iii) computing the location of the satellite based upon the Ephemeris;

iv) computing the satellite clock correction based upon the Ephemeris; and

v) computing the difference between the location and satellite clock corrections which were computed based upon the Almanac and the Ephemeris.